The invention relates to a component having a sliding surface which is intended for the sliding support of another component, wherein the component is made at least partially of a light metal material. The boundary surface of this light metal material is oxidized on the side which faces the sliding surface, and is provided with pores which are open toward the boundary surface. In addition, this boundary surface is provided with a solid lubricant layer.
A component having a sliding surface of the type indicated in the introduction in the form of a composite plain bearing is known, for example, from DE 40 38 139 A1. This plain bearing has a steel support layer which ensures the mechanical strength of the component. An aluminum alloy layer, i.e. a layer made of a light metal material, is applied to said steel support layer, and the boundary surface of said aluminum alloy layer simultaneously forms the surface of the bearing inner side and therefore the sliding surface for the component to be mounted. On the surface, the aluminum alloy has been converted into an aluminum oxide; this can take place, for example, by eloxing. In this process, open pores which can be impregnated with a solid lubricant are produced in the boundary surface. During operation, the solid lubricant is therefore available for lubricating the component to be mounted.
It is also known from the abstract of JP 05025696-A that a boundary layer having pores of aluminum oxide which are open toward the latter serves as a substrate for a coating with a solid lubricant. This then forms a further layer which forms the sliding surface for a component to be mounted on the boundary layer, wherein the solid lubricant also penetrates into the pores which are open toward the boundary layer. This provides reliable anchoring of the solid lubricant layer on the boundary layer.
According to DE 37 24 614 A1, another possibility for increasing the service life of aluminum composite bearings is that the aluminum oxide layer can be saturated with a metal salt which forms a complex with the aluminum oxide. This increases the strength and hardness and also the corrosion resistance of the aluminum oxide layer. However, the improvement in the service life of such an aluminum oxide layer also depends greatly on the material conditions of the mounted component.
According to DE 31 28 412 A1, it is also possible to provide metallic bearings with self-lubricating properties if additives having dry lubricant properties are introduced into the metal matrix of the bearing, which matrix has interspaces for a second matrix of functional additives.
According to EP 1 273 679 A1, it is also possible for a porous layer of aluminum oxide to be applied to a hard material layer which protects the component. By way of example, lubricant particles can then be incorporated in the pores of the aluminum oxide. This produces a functional layer which covers the hard material layer.
It is also known from U.S. Pat. No. 3,206,264 that a porous surface of a base component for bearings can be used to improve the adhesion of an applied layer by increasing the size of the boundary surface between these two materials, and therefore layer adhesion is ensured in the case of bearings subjected to thermal loads even when the two component regions have different coefficients of thermal expansion.
DE 20 2006 006 813 U1 also discloses that a surface of anodically oxidized aluminum with the pores thereby formed can be available for receiving the finest particles of a dry lubricant.